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美国科学家发现核废料清理的新线索
[[作者(Email):张微编译] [发布时间:2017-4-14] [类型:转载] [来源:中国科技网] [关键字:]] [点击:3569] [评论:0] [录入: ]
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华盛顿州立大学一项有关锝-99的化学研究,提升了我们对这种具有挑战性的核废料的认知,而且会让我们找到更好的清理方法。

研究成果发表在《无机化学》期刊上。这项工作是在机械与材料工程学院副教授约翰 麦克洛伊与化学系研究生杰米 韦弗的领导下完成的。并且与太平洋西北国家实验室(PNNL),河流保护办公室、劳伦斯伯克利国家实验室的研究人员进行了合作研究。

锝-99是武器级钚生产的副产物,它被认为是美国环境净化的主要挑战。位于华盛顿州的汉福德核设施,大约有2000磅的元素分散在177个储罐大约5600万加仑的核废料里。

美国能源部正在汉福德建设废物处理厂,想要将危险核废料固定在玻璃中。但研究人员一直没有成功,因为不是所有的锝-99都能纳入到玻璃容器中,挥发性气体也必须被回收到熔化系统里。

该元素易溶于水,当以某些形态存在时,很容易在环境中流转,因此它被认为是一个重大的环境危害。

因为从事锝化合物研究是一项难度很大的工作,所以早期研究使用不易挥发的替代品来研究这种材料的特性。已经有50年时间,没有人研究锝的一些化合物,麦克洛伊说,“该材料的物流管理过程难度相当大,”他说。

华盛顿州立大学的研究是在太平洋西北国家实验室的高度专业化的放射化学处理实验室及环境分子科学实验室内完成的。

研究人员进行了基础化学实验,了解锝-99的特性及其存储方面的独特挑战。他们确定元素的钠形态相比于其他碱形态,表现出很大不同,这可能是与其挥发性相关,也与为什么它易于和水发生反应相关。

“这类化合物的结构和光谱特征,有助于我们加深将锝注入核废料玻璃容器的理解,”麦克洛伊说。

研究人员也希望这项工作将有助于对其他陌生化合物的研究。(张微编译)

以下为英文原文:

Researchers find new clues for nuclear waste cleanup

A Washington State University study of the chemistry of technetium-99 has improved understanding of the challenging nuclear waste and could lead to better cleanup methods.

The work is reported in the journal Inorganic Chemistry. It was led by John McCloy, associate professor in the School of Mechanical and Materials Engineering, and chemistry graduate student Jamie Weaver. Researchers from Pacific Northwest National Laboratory (PNNL), the Office of River Protection and Lawrence Berkeley National Laboratory collaborated.

Technetium-99 is a byproduct of plutonium weapons production and is considered a major U.S. challenge for environmental cleanup. At the Hanford Site nuclear complex in Washington state, there are about 2,000 pounds of the element dispersed within approximately 56 million gallons of nuclear waste in 177 storage tanks.

The U.S. Department of Energy is in the process of building a waste treatment plant at Hanford to immobilize hazardous nuclear waste in glass. But researchers have been stymied because not all the technetium-99 is incorporated into the glass and volatilized gas must be recycled back into the melter system.

The element can be very soluble in water and moves easily through the environment when in certain forms, so it is considered a significant environmental hazard.

Because technetium compounds are challenging to work with, earlier research has used less volatile substitutes to try to understand the material's behavior. Some of the compounds themselves have not been studied for 50 years, said McCloy."The logistics are very challenging," he said.

The WSU work was done in PNNL's highly specialized Radiochemical Processing Laboratory and the radiological annex of its Environmental Molecular Sciences Laboratory.

The researchers conducted fundamental chemistry tests to better understand technetium-99 and its unique challenges for storage. They determined that the sodium forms of the element behave much differently than other alkalis, which possibly is related to its volatility and to why it may be so reactive with water.

"The structure and spectral signatures of these compounds will aid in refining the understanding of technetium incorporation into nuclear waste glasses," said McCloy.

The researchers also hope the work will contribute to the study of other poorly understood chemical compounds.

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